### Spring 2020 Lessons

### Friday Apr 24

- Final Exam will be posted here. Details to follow.

### Class Day: Thurs Apr 23

- Zoom Day. I will invite you to a Zoom Meeting, and you can ask questions about anything you want. Attendance is optional, but I'll be ready with a white board to answer your questions. I hope to do it during our regular class time, so 11:30 to 12:30 Eastern Time.

### No Class Thurs April 16 - Academic Symposium Day

### Class Day: Tues April 14 & Tues April 21 - Lesson 7.3 - Due Fri 4/24/20

- This is a long lesson, so we are counting it for two days.
- Read my enhanced lecture notes, and try to answer the questions as you go along. You can print off the pages, if you want, or you can just read the notes online and take notes on your own paper. But you will not be returning this work to me.
- Do the homework problems described in the lecture notes, then respond via email, as indicated in those notes.

### Class Day: Thurs April 9- Lesson 7.1-2 - due Fri 4/17/20

- Read my enhanced lecture notes, and try to follow along. You can print off the pages, if you want, or you can just read the notes online and take notes on your own paper. But there is nothing in there to return to me.
- Do the homework problems described in the lecture notes, then respond via email, as indicated in those notes.

### Class Day: Tues April 7 - Due Thursday 4/9/20

- Exam Day. I will post the exam (and notify you via email that it has been posted). It will be due at 1:00 Eastern on Thursday, April 9.
- Your exam is here --> LINK

### Class Day: Thurs Apr 2

- Zoom Day. I will invite you to a Zoom Meeting, and you can ask questions about anything you want. Attendance is optional, but I'll be ready with a white board to answer your questions. I hope to do it during our regular class time, so 11:30 to 12:30 Eastern Time.

### Class Day: Tues Mar 31 - Epidemics & ODEs

- My lecture notes are here. This is a lesson that I've done for years, ever since I took an all-day workshop on the topic. But I squeezed it out of the course the last couple times I taught this course in favor of other things. It really seems appropriate that I bring it back for our consideration.
- The best part of all:
**There is no homework to do**for this. Follow through the workbook and try to answer the questions as you go along. Then**email me**to tell me you have completed it. - Get ready for a short "exam" over Chapter 8 (the sections we have covered).
- The review page for Exam 3 is right here.

### Class Day: Thurs Mar 26 - Lesson 8.2c - due Thurs 4/2/20

- Read my enhanced lecture notes, and try to follow along. You can print off the pages, if you want, or you can just read the notes online and take notes on your own paper. But there is nothing in there to return to me.
- Do the homework problems described in the lecture notes, then respond via email, as indicated in those notes.

### Class Day: Tues Mar 24 - Lesson 8.2b - - due Mon 3/30/20

- Read my enhanced lecture notes, and try to follow along. You can print off the pages, if you want, or you can just read the notes online and take notes on your own paper. But there is nothing in there to return to me.

### Class Day: Thurs Mar 19 - Lesson 8.2a - due Fri 3/27/20

- Skim through Section 8.2 in the textbook, though our lesson today only covers the Distinct Real variety of problems. Don't get bogged down in the matrix algebra in the book, or in problems bigger than 2x2. Also, we will cover phase planes next, so you can skim over that quickly for now.
- Email me any other questions you have about the lesson. I may respond with a general reply to all.

**A question you might have**: What about homeworks 6.1 and 8.1 that were both scheduled to come in on Thursday, 3/19? You should still try those problems.

- When you have completed 6.1, email me to let me know, and I will give you full credit. At some point I will post the solutions, but if you want me to look over your version, you can scan or photo your work and send that to me.

- Similarly, let me know when you've completed 8.1 and I will give you full credit. I'll try to post solutions, though those are a little difficult to type up. Perhaps you can send me the phase portrait you generate with the applet below for problem 1. But if you have difficulty getting that to work, don't stress on it.

### * * * * * * * * * * *

Here are some links with a **general connection** to our course:

- SOS Mathematics is a pretty good site for reading about and getting help with differential equations.
- You can find many things online pertaining to the Tacoma Narrows Bridge. I recommend the University of Washington Libraries site.
- Need help evaluating an integral? Try "The Integrator," created by Wolfram Research, the makers of Mathematica.

Here are some links related to **specific topics** in our course:

- For direction field plots (not for systems), look at this Bluffton University page by Darryl Nester. (verified 12-17-19)
- THIS ONE FOR SECTION 8.1: For phase portraits/direction fields (for systems), try this site. (verified 12-17-19).
- If you want to look at a great site for studying many different physics applications (including some we will see in class), look at Walter Fendt's website. (verified 12-17-19)
- An Excel version of the Vibrating Springs spreadsheets can be downloaded by clicking (or perhaps right-clicking) on this link.
- An excellent explanation of the Fourier Transform is here.